Re: kern/58396 (u3g(4): add support for Sierra Wireless MC7304 devices)

[Reinhard Speyerer <rspmn%arcor.de@localhost>]

On Tue, Jul 23, 2024 at 08:48:17PM +0000, riastradh%NetBSD.org@localhost wrote:
> Synopsis: u3g(4): add support for Sierra Wireless MC7304 devices
> 
> State-Changed-From-To: open->feedback
> State-Changed-By: riastradh%NetBSD.org@localhost
> State-Changed-When: Tue, 23 Jul 2024 20:48:16 +0000
> State-Changed-Why:
> Thanks for the patch!  Does this work better now in HEAD?
> 
> If so, we should probably do pullup-10 and pullup-9 -- seems like a
> reasonably low risk.

When doing pullups it might make sense to apply this part of the diff
from PR 56145 to if_umb.c 1.26

--- if_umb.c.orig	2024-07-24 22:14:17.939793557 +0200
+++ if_umb.c	2024-07-24 22:16:17.935789331 +0200
@@ -407,5 +407,8 @@
 	for (i = 0; i < uiaa->uiaa_nifaces; i++) {
-		id = usbd_get_interface_descriptor(uiaa->uiaa_ifaces[i]);
-		if (id != NULL && id->bInterfaceNumber == data_ifaceno) {
-			sc->sc_data_iface = uiaa->uiaa_ifaces[i];
+		if (uiaa->uiaa_ifaces[i] != NULL) {
+			id = usbd_get_interface_descriptor(uiaa->uiaa_ifaces[i]);
+			if (id != NULL && id->bInterfaceNumber == data_ifaceno) {
+				sc->sc_data_iface = uiaa->uiaa_ifaces[i];
+				uiaa->uiaa_ifaces[i] = NULL;
+			}
 		}

and then do pullups for that too.

Otherwise NetBSD users who build their kernel with umb(4) enabled will see
a kernel panic after they switch their MC7304 to MBIM mode and powercycle
or reset it.

Not sure if the other parts of the diff are still relevant since there have
been several updates to if_umb.c and the NetBSD networking stack in the
meantime. Please consider closing PR 56145 after applying the patch above.

Thanks,
Reinhard